The objective of the present study is to examine the psychosocial contexts of attachment relationships in families with unipolar depressed, bipolar depressed and well mothers. Since children of emotionally disturbed parents are at high risk for developing emotional and behavioral problems, this high-risk sample of affectively ill mothers and their children provides an opportunity to answer important questions about the organization of normal and atypical behavior. The aim of the research is to identify factors that put children at risk for psychosocial disorders and, further, to understand the processes and mechanisms by which these factors operate. Attachment assessments and behavioral observations are made as part of the longitudinal study. Analysis of these data revealed that mothers with bipolar illness are more likely than well mothers to have children who are insecurely attached. Affective behavior expressed by both mother and child was strongly related to attachment security. For example, there is a striking link between mother's downcast negative mood and insecure attachment but this is only true for depressed mothers and their children.